Saturday, August 14, 2010

This year, there are so many choices when it comes to pick a cloud storage vendor, such as Amazon S3, Windows Azure, AT&T Synaptic Storage, Nirvanix, Peer1 CloudOne, EMC Atmos, Mezeo, Google Storage and etc. If you are seriously thinking about expanding your IT infrastructure with Cloud Storage Services, who do you pick and what are the factors to consider?

1. Service level agreement

The first thing you need to check out is the Service Level Agreement. You need to see what is the durability of the data object and the availability of the data objects. The durability should be between 99.99%-99.999999999% and the availability should be > 99.9%.

For example, Amazon S3 has two levels of pricing based on the durability.

2. How many locations the vendor stores your data

If the vendor gives out the information in the public, it is good. If not, you need to follow up and see how the vendors support the durability and availability. Is your data stay together in one site or two sites; in one cage or two cages; in one rack or two racks …

It is more expensive to store data in two different sites. However, in case there is an Internet glitch to one site, the other site is still available.

3. How long the vendors has been in service

Amazon S3 could be the longest in the market so it could have gone through more growing pain than the other vendors. It is both good and bad. Good part is that it has more experience. The bad is that if everyone is picking Amazon S3, it could be busier.

4. Your location and speed

You will typically need to find out where is the closest data center to you. Finding a cloud service vendor that has a data center close to you has big speed advantage. Shorter latency and faster respond time will make cloud storage more useful.

There are several ways to test the speed. First is that you could do a ping to the Service API end point. If you don’t bother to find the API end point, you can use tools such as Gladinet Cloud Desktop to mount each cloud storage services and do drag and drop upload/download test to compare. There are several articles on Gladinet blog on how to compare them.

5. Talk to your managed hosting service provider

Hosting service providers such as Rackspace, The Planet, Peer1 and etc are among the first tiers to offer cloud storage service.

If you are using services from them already, you need to check out first if they offer cloud storage. A lot of them provide free transfer among their server and their cloud storage service.

It could be a form of vendor lock-in but it could provide big price break if you are using cloud storage services actively.

6. Pricing

We didn’t talk about pricing early. It is not because price is not important, it is because it is hard to differentiate vendors because they are all offering similar pricing. The biggest price break will come from the 5 above if the vendor waives some data transfer fees.

7. Speed again

Speed is like the air in the tire, you need to check constantly.

If you are doing a backup job, the difference of getting it done in a day or two days may not matter. But when you are doing disaster recovery and doing cloud restore, a day or two days does matter a lot.

This is very important because the bottleneck typically is on the cloud storage vendor side. Can the vendor scale quickly if demands come in.

8. Pricing again

When you see your first month of cloud storage usage bill, you may feel the price is good. This is why you started in the first place. However, there is data transfer cost and you haven’t initiate too much download yet! So your behavior and usage pattern could affect the monthly bill later on. If your main use case is backup and restore to the cloud, you know that you are not going to have much transfer cost. If your usage pattern is different, you will need to plan a little ahead for the usage.

The above factors could help you choose a public cloud storage service vendor. If you are a big enterprise and doing private cloud deployment, the factors could be different when the vendor list is different too.